(a) Field of the Invention
This invention relates to a new system for the fabrication of countertops or the like, and to an edge moulding element for use in this system.
(b) Description of the Prior Art
Domestic countertops used in kitchens, bathrooms and the like have hitherto usually been fabricated as plastic laminates on fiber-board backing or as gel-coated synthetic marbles. Typically these have had finishes of no more than 0.062-inch thickness so that they cannot withstand sanding or polishing to remove traces of heavy wear or other damage.
In more recent times, solid surfacing sheets of man-made material, generally of polyester or acrylic composition, have become available. These are typically supplied in 1/2-inch and 3/4-inch thicknesses and are intended for fabrication into horizontal countertops (their major area of use) and vertical wall surfaces, as in tub and shower surrounds, and for use in some furniture applications. These sheets are homogeneous in nature, and besides offering a stain and chemical resistance that is far superior to any natural products, have the advantage that surface scratches and marks such as produced by knife cuts or cigarette burns can be sanded and polished out to leave no visible change in the colour or texture of the surface. Sheet material of this type is sold by, among others, DuPont Corporation under the trademark CORIAN, Avonite Corporation under the trademark AVONITE, Nevamar Corporation under the trademark FOUNTAINHEAD, Cyanamid Limited under the trademark 2000X and Laurentian Industries (North Bay) Limited under the trademark SOLIDEX.
In the fabrication of countertops and like applications such as table tops and mantel pieces, it is usually desirable to provide an edge treatment that is very much thicker than the stock thickness of the sheet; typically it will be at least 1.5 inches. To satisfy this requirement, the fabricator cuts the sheet material to the required size and shape for the product being made, and then cuts and glues to the edge of the sheet additional strips of sheet material in order to build up sufficient thickness or mass to permit the required edge detail to be formed. Apart from the labour involved in cutting and gluing the edge strips, the process is complicated by the need to ensure that the edge strips do not shift out of position when clamp pressure is applied to maintain contact between the strips and the sheet while the glue is curing. In some procedures, temporary stop blocks are first glued to the underside of countertop to prevent the edge strips from shifting when the strips are being glued. Moreover the wet glue joint is susceptible to permanent discoloration if it becomes soiled, for example, by contact with dirty fingers when the fabricator attempts to verify or ensure proper alignment between the edge strip and the sheet. If two or more layers of edge strip are required, such difficulties are multiplied. Fabrication is further delayed by the fact that some of the specialized adhesives require between two and eight hours to cure before any further layering or processing can be performed. The difficulties increase wherever corners are required.
The demand for accuracy and extreme care in fitting edge strips to countertops means that skilled workers are required for the task, and accordingly the cost of the finished product reflects their high wages.
The aim of the invention is to provide an improved edge moulding element and a new fabrication system that will alleviate the difficulties described above.